One of the best-selling pieces of choral music of the late twentieth century, the motet "O Magnum Mysterium" ("O Great Mystery") epitomizes the the style of it's composer, American Morten Lauridsen. In this four-part a cappella chorus work, Lauridsen takes a centuries-old Latin text describing the Nativity scene, imbues it with closely-voiced chords, colored by suspensions or or quietly dissonant tones, and creates a restrained, simple setting that develops at an unhurried pace.